After having installed the trial version and starting up the application, I get a message at the bottom saying "you have 2 pixinsight updates". These are 1. Pixinsight Ref Documentation snapshot-2010 Dec20, and 2. Pixinsight Core application Version 1.6.9.652 ( bug fix).
I select all and apply and they download.
I get notification: packages downloaded, 2 successful etc.
Note says updates will be installed when you exit this instance of the Pixinsight Core Application.
I click on ok.
When exit Pixinsight, message comes up about update packages scheduled for installation, I click on yes, with tick inside the restart pixinsight box.
Pixinsight starts and I get a message that the update process has failed, nothing shown in the update log.
Pixinsight starts ok with the message at the bottom re: I have 2 updates, and the cycle continues.
NOTE; I noticed another post regarding this problem and having unchecked the protect my computer box, the updates have installed successfully.